Lawn mower

ABSTRACT

A rotary-type lawn mower having a housing and three cutter heads, each of which includes a blade mounted to rotate about a vertical axis, are mounted in triangular relation within the housing. One of the cutter heads is located along the longitudinal center line of the housing while the other cutter heads are located forwardly and laterally outward of the central cutter head. Wheels are mounted on opposite sides of the housing and the wheels are positioned so that the cutting zone of each forward cutter head is located a substantial distance ahead and laterally outward of the respective wheel. A third pivotable wheel is attached to the rear end of the housing to said in steering.

United States Patent [1 1 Haseloff Dec. 25, 1973 1 1 LAWN MOWER2,582,177 1/1952 Swisher ct a1. 180/19 s [76] Inventor: Fritz Haseloff,Behingstrasse 3,

Germany Primary Examiner-Antonio F. Guida [22] F ed: Mar. 20, 1972Att0rneyAndrus, Sceales, Starke & Sawall [21] Appl. No.: 236,147

[5 7 ABSTRACT A rotary-type lawn mower having a housing and three 30Forei n A l' t'on P r't D ta l g pp 1 no I y a cutter heads, each ofwhich includes a blade mounted Mar. 29, 1971 Germany P 21 15 101.9 torotate about a vertical axis are mounted in trianglk lar relation withinthe housing. One of the cutter 2% 8 6 heads is located along thelongitudinal center line of I 1 l2 1 the housing while the other cutterheads are located [58] Field of Search 56/135, 13.6, 6,

56 2 0 forwardly and laterally outward of the central cutter 8 M711180/19 S head. Wheels are mounted on opposite sides of the housing andthe wheels are positioned so that the cut- [56] References cued tingzone of each forward cutter head is located a sub- UNlTED STATES PATENTSstantial distance ahead and laterally outward of the re- 3,152,43110/1964 Ott et al 56/295 Spective wheel. A third pivotable wheel isattached to 2,763,1 16 9/1956 Flinchbaugh 56/13.6 the rear end of thehousing to said in steering. 2,898,723 8/1959 Goodall 56/13.6 3,196,9717/1965 Schantz 180/19 S 5 Claims, 2 Drawing Figures I I 5 17 10 19 73 7I 3 1 LAWN MOWER BACKGROUND OF THE INVENTION Various types of lawnmowers are presently utilized, for instance those powered by gasolineengines or electric motors, those propelled manually, and so-called lawntractors or riding mowwrs All of these lawn mowers have the drawback inthat the carriage wheels, in order to allow travel of the unit, arelocated on the outside of the rotating blade system. Thus it is verydifficult to effectively cut the edge of the lawn when the lawn or grassis situated at a higher level than the earth next to it. During mowingin the vicinity of the edge, or on the edge itself, not only is handlingof the mower difficult, but the cutting process'becomes critical, inthat when the mower is moved to the edge of the lawn, the edge may breakoff, or before the blade system reaches the outermost portion of thelawn edge, the front wheels of the mower hangin the air and the mowerdrops to the surrounding earth under its own weight. When the mowerdrops, the blade may destroy the edge of the lawn, and may also becomeblocked in the soil. When operating on the edge of the lawn, theoperator may try to keep the mower in equilibrium during the drop, butapart from the necessity of exerting considerable force, it requiresconsiderable skill.

With the use of conventional lawn mowers, it is also difficult to mow alawn edge along its length. In such a case, onepair of wheels ride onthe lawn and the other pair of wheels ride on .the earth, and theinclined position of the lawn mower reduces the effectiveness of thecutting.

It is not possible, with the use of conventional rotary lawn mowers, tocut the grassall the way up to the trunk of a tree or other post, sincethe blade and the post or tree make contact only at a given point. Thecomplete removal of grass can be obtained only by additional cutting byhand shears or by repeated approach with the mower.

In the same manner it'is also difficult to cut the edge of lawnsbordered by rocks, curbs, or slab paths, since only in rare instances isthe surface of the curb or the path at the same level as the surface ofthe lawn. As a consequence, the lawn mower tends to tilt due to thedifference in levels, resulting in ineffective cutting and possibledamage to the blade system.

The conventional lawn mower is at most steerable in a limited manner.After making one pass, it is necessary to rotate the mower 180 for thenext pass, or in the case of square mowing to rotate the mower by 90,and in so rotating the mower, the cut grass area is scarred.

With the so-called riding mowers, the same problems arise and the lawnmowing is even more critical, since the blade system is beneath therider and he cannot see the actual operating position.

SUMMARY OF THE INVENTION The present invention tends to eliminate thedrawbacks that have been associated with conventional lawn mowers. Inaccordance with the present invention, the lawn mower includes threecutter heads that are disposed in such a manner that, in the directionof travel of the lawn mower, two cutter heads are located forwardly andthe third cutter head is positioned behind and centrally of the twoforward cutter heads. The cutting zones of the forward cutter heads, aswell as the rear cutter head extend both longitudinally and transverselyover the path of travel of the wheels, so that the wheels can be safelysituated on the lawn surface, while the blades of the cutter heads fullycover the lawn edges. Furthermore, the blades of the cutter heads canalso be brought intoa position where they partially surround posts,trees, etc., and thus the mower provides more effective cutting of thegrass close to these objects.

Other objects and advantages will appear in the course of the followingdescription.

DESCRIPTION OF THE DRAWINGS The drawing illustrate the best modepresently contemplated of carrying out the invention.

In the drawings:

FIG. 1 shows a lawn mower with motor drive viewed from the side, partlyin section; and

FIG. 2 is a top plan view of the lawn mower shown in FIG. 1.

The lawn mower 1 shown in FIGS. 1 and 2, comprises three cutter heads 2,3, and 4 having cutter blades 5. Cutter heads 2, 3, are situatedlaterally outward and ahead, in the direction of mower travel, of thecenter cutter head 4.

The cutter heads 2, 3, and 4 are incorporated in a chassis or housing 6that also forms a protective. cover. On the chassis 6 aredisposedcarriage wheels 7 and a steering wheel 8 that is supported in a pivotmounting 9. The outwardly extending legs 10 of the pivot mounting 9carry a handle 11. l

The drive motor or engine 12 is situated, for the purpose of balancingthe weight of the cutter heads 2, 3, 4, in the triangle defined by thecarriage wheels 7 and of the steering wheel 8 in a compartment of thehousing 6. The blades 5 are driven by motor drive 12 by suitabletransmission members 13, preferably by cable, V-belt or chain drive. Inthe case of belt drives, it is possible by the selection of suitablematerials and/or by corresponding angle of grip, to differentiate thefriction resistance in such a manner to provide a slip coupling, so thata blade blocked by a foreign body stops and cannot be forcibly damaged.

It is contemplated that the blades 5 can be driven by the carriagewheels 7 by means of a transmission, not shown in the drawings. It isalso contemplated that the position of cutter heads 2, 3, could beadjusted around the center cutter head 4, to provide an adjustablecutting width for the lawn mower l.

The drawings do not show the mechanism that regulates the height of cut,nor the baffle plates for the ejection of the grass, both of which areconventional features.

The cutter heads 2, 3, 4, are positioned in relation to carriage wheels7 so that the cutters heads 2, 3, 4 extend forwardly of the carriagewheels 7 of the mower 1 in the direction of mower travel. Thus thecarriage wheels 7 can be situated on the lawn 14 with the outer edges ofthe cutter heads 2, 3, 4, projecting over the ground 16, to enable thelawn edge 15 to be clearly cut, as shown in FIG. 1.

For the mowing of a longitudinal edge 17, both the left or the rightcutter head 2, 3, extends laterally beyond the corresponding carriagewheel 7, so that, as shown in FIG. 2, the carriage wheel 7 can ride onthe lawn a substantial distance from the longitudinal edge 17 on theground 16 and because of the overhang, the

cutter head 2 will cut the lawn 14 up to the longitudinal edge 17.

With the present cutter system, it is also possible to mow a lawn corner18 formed by the lawn edge and longitudinal edge 17, without the lawnmower dropping to the ground 16. In the same manner, there are noproblems in mowing the lawn 14 directly up to the wall 19 or to rockcurbs, or to slab paths.

As the cutter heads 2, 3, 4, are staggered in a triangle, and as thecutter heads 2 and 3 are housed within separate, generally cylindricalsections of housing 6, the cutting of the grass adjacent laundry postsor trees 20 up to medium size is facilitated, since the cutter heads 2,3, and 4 partially surround the object 20, as shown in FIG. 2.

As a further advantage, the turning of the mower during mowing is madeeasier by the steering wheel 8 that is steered by handle 11.

Finally, it should be pointed out that because of the three relativelysmall cutter heads 2, 3, 4, in relation to the total size of the lawnmower 1 and in relation to the small weight of the unit, it is possibleto obtain a relatively wide cutting width of, for example, 28 inches,something that normally is possible only with larger riding-type mowers.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

I claim:

1. A lawn mower, comprising a housing including a main housing sectionand a pair of generally cylindrical outer housing sections thatcommunicate with said main section; each of said outer housing sectionsbeing located laterally outward and forwardly of the main housingsection, the forward extremity of the main housing section being locatedto the rear of the forward extremities of the outer housing sections toprovide the housing with a central forwardly facing recess, a centralcutter head located within the forward portion of the main housingsection and including a blade mounted for. rotation on a vertical shaft,a pair of outer cutter heads with each outer cutter head being disposedin an outer housing section and each outer cutter head including a blademounted for rotation on a vertical shaft, a pair of wheels journalled onopposite sides of the main housing section with each wheel located tothe rear of the corresponding outer housing section, each outer housingsection extending a substantial distance laterally outward of thecorresponding wheel and extending forwardly from the corresponding wheelin the direction of mower travel, a third wheel mounted on the mainhousing section and located to the rear of said pair of wheels, anddrive means carried by the housing and operably connected to thevertical shaft of each cutter head to drive the respective blades.

2. The lawn mower of claim 1, wherein said drive means includes a primemover and a belt drive mechanism operably connecting the output of theprime mover with the shafts of the respective cutter heads.

3. The lawn mower of claim 1, wherein the axes of the wheels are locatedto the rear of the vertical shaft of the central cutter head.

4. The lawn mower of claim 1, and including pivotal means for pivotallyconnecting said third wheel to the rear portion of the main housingsection.

5. The lawn mower of claim 4, wherein said pivotal means includes a pairof generally horizontal outwardly extending legs, and a handle connectedto said legs.

1. A lawn mower, comprising a housing including a main housing sectionand a pair of generally cylindrical outer housing sections thatcommunicate with said main section; each of said outer housing sectionsbeing located laterally outward and forwardly of the main housingsection, the forward extremity of the main housing section being locatedto the rear of the forward extremities of the outer housing sections toprovide the housing with a central forwardly facing recess, a centralcutter head located within the forward portion of the main housingsection and including a blade mounted for rotation on a vertical shaft,a pair of outer cutter heads with each outer cutter head being disposedin an outer housing section and each outer cutter head including a blademounted for rotation on a vertical shaft, a pair of wheels journalled onopposite sides of the main housing section with each wheel located tothe rear of the corresponding outer housing section, each outer housingsection extending a substantial distance laterally outward of thecorresponding wheel and extending forwardly from the corresponding wheelin the direction of mower travel, a third wheel mounted on the mainhousing section and located to the rear of said pair of wheels, anddrive means carried by the housing and operably connected to thevertical shaft of each cutter head to drive the respective blades. 2.The lawn mower of claim 1, wherein said drive means includes a primemover and a belt drive mechanism operably connecting the output of theprime mover with the shafts of the respective cutter heads.
 3. The lawnmower of claim 1, wherein the axes of the wheels are located to the rearof the vertical shaft of the central cutter head.
 4. The lawn mower ofclaim 1, and including pivotal means for pivotally connecting said thirdwheel to the rear portion of the main housing section.
 5. The lawn mowerof claim 4, wherein said pivotal means includes a pair of generallyhorizontal outwardly extending legs, and a handle connected to saidlegs.